Late-stage, or Phase III, trials are ongoing to confirm the findings, researchers said, and to test whether the vaccine protects against infection with SARS-CoV-2 in a broad range of people, including people with underlying health conditions.
Results of those trials should be known by Christmas, the Oxford Vaccine Group’s director Andrew Pollard said, adding it was too early to know whether and how well the vaccine works in actually preventing COVID-19.
“We haven’t quite got to that point yet. We’re obviously not going to rush that,” he told BBC radio. “We’re getting close, and it’s definitely going to be before Christmas, based on the progress.”
The Oxford/AstraZeneca COVID-19 vaccine candidate, called AZD1222 or ChAdOx1 nCoV-19, had been among the front-runners in global efforts to develop shots to protect against infection with the novel coronavirus, or SARS-CoV-2.
But rival drugmakers Pfizer/BioNTech and Moderna have in the past 10 days edged ahead, releasing data from late-stage COVID-19 vaccine trials that show more than 90 per cent efficacy.
Unlike the Pfizer/BioNTech and Moderna shots, both of which use new technology known as messenger RNA (mRNA), AstraZeneca’s is a viral vector vaccine made from a weakened version of a common cold virus found in chimpanzees.
The Phase II trial reported in The Lancet involved a total of 560 healthy volunteers, with 160 aged 18-55 years, 160 aged 56-69 years, and 240 aged 70 or over.
Volunteers got two doses of the vaccine or a placebo, and no serious side effects related to the AZD1222 vaccine were reported, the researchers said.
AstraZeneca has signed several supply and manufacturing deals with companies and governments around the world.
Australia has so far secured 33.8 million doses of the AstraZeneca/Oxford vaccine candidate. The government has also signed a deal to have the vaccine vaccine produced in Australia by the pharmaceutical manufacturer CSL.